Lens, manufacturing method thereof and light emitting device package using the same

ABSTRACT

A lens and a light emitting device package formed by introducing surface mount technology (SMI) are disclosed. The lens includes a refractive portion which refracts incident light, and at least one surface mount portion, wherein a portion of the surface mount portion is formed in the refractive portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of prior U.S. patentapplication Ser. No. 11/902,779 filed Sep. 25, 2007, which claimspriority under 35 U.S.C. §119 to Korean Application Nos. 10-2006-0094629filed on Sep. 28, 2006, whose entire disclosures are hereby incorporatedby reference.

BACKGROUND

1. Field

The present invention relates to a lens and a manufacturing methodthereof, and more particularly to a lens and a light emitting devicepackage formed by introducing surface mount technology (SMT).

2. Background

Along with the development of fields using light, parts using opticalmaterials have been widely used in an optical communication device, anoptical storage device, medical optical equipment and the like invarious industrial fields. The parts using optical materials include acommonly-used lens, a prism, a beam splitter, a reflection mirror and adiffraction grating.

In the parts using optical materials, the lens is classified into aspherical lens, an aspherical lens, a ball lens, a GRIN lens and thelike. Also, the lens is classified into an epoxy lens, a glass lens, asilicone lens and the like according to a material of the lens.Recently, a technology is being developed for a small-sized lens, alightweight lens, a high-performance lens, and a lens having a largeaperture. Particularly, along with the development of a light emittingdiode (LED) industry, the demand and requirement for camera flash lensesof portable phones and lenses of LCD products using LED backlightsources are increasing.

Although the glass lens has high chemical and heat resistance, moldingof the glass lens is complicated and expensive compared to molding ofpolymeric materials. Thus, a method of manufacturing glass by moldingpolymeric materials has been widely used.

Further, an injection molding method using a mold is widely used as amethod of manufacturing a lens. In the injection molding method, aviscous fluid such as silicone gel or epoxy is injected into the moldand then molded, and the mold is separated, thereby manufacturing alens. The lens manufactured by the above-mentioned method is installedat a specified position of a device having a light emitting device suchas a light emitting diode or a laser diode. The lens refracts lightemitted from the light emitting device to change a light path.

In a conventional method, cream solder having high electric and heatconductivity are formed at portions of light emitting devices of PCB bypatterning cream solder only at desired positions using a mask.Electronic devices such as light emitting diodes and Zener diodes arearranged and positioned on the cream solder pattern. The cream solder isheated to a temperature higher than a melting point and cooled down and,thus, electric and optical devices and the metal pattern of PCB areelectrically and mechanically connected. That is, after the electric andoptical devices are connected, epoxy with high adhesivity is bonded to aportion for mounting a lens, and the lens is mounted on the portion withepoxy by a transfer device. Then, when heating to an appropriatetemperature and cooling, the lens is bonded to PCB through epoxy.

However, the bonding process should use epoxy capable of bonding at atemperature less than the melting point of the cream solder.Accordingly, there is a limit in selecting the epoxy and cream solder.Since the electric and optical devices are connected and the lens isbonded, the processing time increases. Also, since the light emittingdevices are connected to PCB and the lens is bonded after increasing thetemperature, the PCB may become twisted. Thus, it is impossible toaccurately arrange the light emitting devices and lens and the unit costincreases.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a lens, amanufacturing method thereof and a light emitting device package usingthe same that substantially obviate one or more problems due tolimitations and disadvantages of the related art.

An object of the present invention is to provide a method of accuratelyarranging a light emitting device and a lens on a substrate.

Another object of the present invention is to provide a method ofarranging a light emitting device and a lens on a substrate by a simpleprocess and with the inexpensive cost.

Additional advantages, objects, and features of the invention will beset forth in part in the description which follows and in part willbecome apparent to those having ordinary skill in the art uponexamination of the following or may be learned from practice of theinvention. The objectives and other advantages of the invention may berealized and attained by the structure particularly pointed out in thewritten description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with thepurpose of the invention, as embodied and broadly described herein, alens includes a refractive portion which refracts incident light; and atleast one surface mount portion, wherein a portion of the surface mountportion is formed in the refractive portion.

In accordance with another aspect of the present invention, there isprovided a method of manufacturing a lens comprising preparing at leastone surface mount portion; and forming a lens in a region including aportion of the surface mount portion.

In accordance with yet another aspect of the present invention, there isprovided a light emitting device package comprising a substrate with alight emitting device; a lens which refracts light emitted from thelight emitting device and transmits the light; and at least one surfacemount portion which fixes the lens on the substrate.

It is to be understood that both the foregoing general description andthe following detailed description of the present invention areexemplary and explanatory and are intended to provide furtherexplanation of the invention as claimed

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this application, illustrate embodiment(s) of the invention andtogether with the description serve to explain the principle of theinvention. In the drawings:

FIGS. 1A to 1E show cross-sectional views of a lens according to anembodiment of the present invention;

FIG. 2 shows a flowchart of a lens manufacturing method according toanother embodiment of the present invention;

FIGS. 3A to 3F show the lens manufacturing method according to anotherembodiment of the present invention; and

FIG. 4 shows a cross-sectional view of a light emitting device packageaccording to yet another embodiment of the present invention.

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Hereinafter, an embodiment of the present invention will be described indetail with reference to the accompanying drawings.

A dimension of a thickness is enlarged in the accompanying drawings toclearly represent several layers and regions. A thickness ratio ofrespective layers shown in the drawings is not necessarily a realthickness ratio. Meanwhile, when a portion such as a layer, a film, aregion and a plate is formed or disposed “on” the other portion, itshould be understood that the portion may be formed directly on theother portion through a direct contact, or another portion may bedisposed therebetween.

A lens according to the present invention has metal leads formed at thelower end of the lens to use surface mount technology (SMT).Accordingly, the lens can be quickly and easily fixed on a substratehaving a light emitting device formed thereon through the metal leads.

FIGS. 1A to 1E show cross-sectional views of the lens according to theembodiment of the present invention. The lens according to theembodiment of the present invention will be described with reference toFIGS. 1A to 1E.

The lens according to the embodiment of the present invention includes arefractive portion 110 and surface mount portions 120. A portion of thesurface mount portions 120 is formed inside the refractive portion 110.Preferably, the refractive portion 110 is formed of the same material inthe same shape as a general lens. The refractive portion 110 refractsincident light to change a light path and transmit the light. Therefractive portion 110 may be formed of thermosetting resin such assilicon, epoxy, PC and PMMA or thermoplastic resin. Further, therefractive portion 110 may be formed of resin for a processing of fixingthe surface mount portions 120 as will be described below. Further,although the refractive portion 110 is represented in a hemisphericalshape, the refractive portion 110 may be formed in a different shapecapable of refracting a path of the incident light. Specifically, therefractive portion 110 may be formed in a spherical or non-sphericalshape, or in a shape having sectional curvature or bisectionalcurvature, preferably, having at least one curvature.

Each of the surface mount portions 120 includes a first part 120 b and asecond part 120 a. The second part 120 a is fixed into the refractiveportion 110 and the first part 120 b is fixed on the substrate and thelike to fix the refractive portion 110. Further, although two surfacemount portions 120 are provided in FIG. 1, at least one surface mountportion may be disposed. As the number of the surface mount portionsincreases, the lens can be firmly fixed on the substrate, but the costmay increase.

The surface mount portion 120 is a device for mounting a part on thesubstrate as one example of a surface mount device (SMD). In thisembodiment, the surface mount portion 120 includes the first part 120 band the second part 120 a. The second part 120 a is fixed into therefractive portion 110 and may be fixed into the refractive portion 110through a resin hardening process or the like, as will be describedbelow. Further, the first part 120 b is exposed to the outside of therefractive portion 110 and may be fixed on the substrate through a lightemitting device manufacturing process.

The surface mount portion 120 may be formed of one metal selected from agroup consisting of Au, Ag, Cu and Al. Further, although the surfacemount portion 120 is represented in a

shape, the surface mount portion 120 may have any shape capable offixing the part on the substrate, for example, and

and ‘⇓’ as shown in FIGS. 1B to 1E.

The lens according to the embodiment of the present invention can befixed on the substrate with the surface mount portions through a simpleprocess.

FIG. 2 shows a flowchart of a lens manufacturing method according toanother embodiment of the present invention. FIGS. 3A to 3F show thelens manufacturing method according to another embodiment of the presentinvention. The lens manufacturing method according to another embodimentof the present invention will be described with reference to FIGS. 2 to3F.

The method includes a step of preparing surface mount portions andfixing the surface mount portions to a lens. Specifically, as shown inFIG. 2, the method includes a step S210 of fixing surface mount portionson first molds, a step S220 of fixing a second mold on the first moldswith the surface mount portions and injecting a lens material into thesecond mold, and a step S230 of processing the lens material to form alens and removing the first and second molds.

First, surface mount portions 310 and first molds 300 a and 300 b areprepared. Although the surface mount portions 310 are provided as a pairof surface mount portions in a shape similar to

in FIG. 3A, at least one surface mount portion may be disposed. As thenumber of the surface mount portions increases, there is an advantage infixing the lens, but there is a problem such as an increase in the cost.The surface mount portions 310 are formed of metal such as Au, Ag, Cuand Al. The surface mount portions 310 may be formed of any materialcapable of fixing the lens to the substrate. The surface mount portions310 are bent in a

shape such that they can be easily fixed on the first molds 300 a and300 b, the lens, and substrate as will be described below. In this case,as described above, the surface mount portions 310 may have anothershape such as and

and ‘⇓’ as well as the

shape.

Each of the surface mount portions 310 includes a second part to befixed on the lens and a first part to be fixed on the substrate.Further, the first molds 300 a and 300 b are provided as a pair of firstmolds in a hexahedral shape as shown in FIG. 3A. In this embodiment, thefirst molds 300 a and 300 b are not necessarily formed in a hexahedralshape and it is sufficient if the process of fixing the surface mountportions can be performed with two first molds. Further, the first molds300 a and 300 b may be formed of any material capable of fixing thesurface mount portions 310.

Then, as shown in FIG. 3B, the surface mount portions 310 are fixed onthe first molds 300 a and 300 b. In this case, preferably, the surfacemount portions 310 are firmly fixed in a space formed in the first molds300 a and 300 b. When a portion of the first molds 300 a and 300 b ismelted to fix the surface mount portions 310, there is a problem in thefollowing separation process. Accordingly, it is not allowed that thefirst molds 300 a and 300 b are melted to mix with the surface mountportions 310 formed of Au, Ag, Cu, Al, or the like. In FIG. 3B, a leftportion 300 a and a right portion 300 b of the first molds are puttogether to fix the surface mount portions 310 in an inner space. Thatis, in FIG. 3B, the surface mount portions 310 are fixed in the firstmolds, and the surface mount portions 310 are surrounded by the firstmold 300 a such that they are not shown at the outside.

Then, as shown in FIGS. 3C and 3D, a second mold 320 is fixed on thefirst molds 300 a and 300 b with the surface mount portions 310 fixedthereon, and a lens material 325′ is injected into the second mold 320.The lens material 325′ may be formed of thermosetting resin such assilicon, epoxy, PC and PMMA or thermoplastic resin. In this case, thesecond mold 320 should not be mixed with the lens material 325′.

First, as shown in FIG. 3C, the second mold 320 is formed on the firstmolds 300 a and 300 b with the surface mount portions 310 fixed thereon.In FIG. 3C, the second mold 320 is represented as a hexahedron having anempty space 325 of a hemispherical shape. The lens material is injectedinto the empty space 325 to form a lens. Accordingly, the empty space325 may be formed differently according to the shape of a lens to beformed. Further, the second mold 320 is fixed on the first molds 300 aand 300 b such that the lens material is injected into the empty space325 as will be described below. Further, the surface mount portions 310should be positioned in the empty space 325 inside the second mold 320.

Then, as shown in FIG. 3D, the lens material 325′ is injected into thesecond mold 320. Since the lens material 325′ is injected through thefirst molds 300 a and 300 b and the second mold 320, a passage forinjecting the lens material is disposed in the first molds or the secondmold. The lens material 325′ is injected with fluidity and filled in aninner space of the second mold 320. When the process of injecting thelens material 325′ is completed, the surface mount portions 310 arepositioned in the lens material 325′.

Further, the lens material 325′ is processed through a hardening processof cooling the lens material 325′ to form a lens. In this case, aportion of the surface mount portions 310 should be firmly fixed intothe lens and the first and second molds should be easily separated fromthe lens.

Then, when the first and second molds are removed, as shown in FIG. 3E,the lens is completed. That is, the surface mount portions 310 areformed in the completed lens 325′. Although a pair of -shaped surfacemount portions 310 is shown in FIG. 3E, the number and shape of thesurface mount portions 310 may vary if they can fix the lens to thesubstrate. In this embodiment, a portion referred to as a “lens” isequal to a portion referred to as a “refractive portion” in the aboveembodiment of the lens.

After the surface mount portions 310 are positioned in the lens material325′, the lens material 325′ is hardened to fix the surface mountportions 310. However, as shown in FIG. 3F, the surface mount portions310 may be formed in a screw shape and the screw-shaped surface mountportions 310 may be inserted and fixed into the lens.

The lens manufactured by the lens manufacturing method according to theembodiment of the present invention may be easily and firmly fixed onthe substrate or the like through the surface mount portions.

FIG. 4 shows a cross-sectional view of a light emitting device packageaccording to yet another embodiment of the present invention. The lightemitting device package according to yet another embodiment of thepresent invention will be described with reference to FIG. 4.

The light emitting device package with the above-described lens includesa light emitting portion 410 formed on a substrate 400 and the lens 325′fixed on the substrate 400 through the surface mount portions 310. Thesubstrate (printed circuit board; PCB) 400 includes a circuit fordriving a light emitting device and the like and the surface mountportions 310 are fixed on the substrate 400. Further, if the substrate400 is formed of silver or white epoxy-based PSR resin or the like, itis possible to increase reflectivity of the light emitting devicepackage. Further, the substrate 400 may be formed of a semiconductormaterial such as Si, ceramic or a resin material. The substrate 400 mayinclude a single layer made of the above-mentioned material or multiplelayers. In this case, the respective layers may be formed of the samematerial or different materials. When the substrate 400 is formed of thesame material, the material of the substrate 400 may be patterned by anetching method or the like. When the substrate 400 is formed ofdifferent materials, the respective layers that have been patterned maybe stacked.

Although the first parts 310 b of the surface mount portions 310 arefixed on the surface of the substrate 400 in FIG. 4, the first parts 310b may be inserted and fixed into the substrate 400. Further, the secondparts 310 a of the surface mount portions 310 are fixed on the lens325′. Further, since the light emitting portion 410 is surrounded by thelens 325′, light emitted from the light emitting portion 410 isrefracted through the lens 325′ and then emitted to the outside while alight path is changed. Although the light emitting portion 410 issurrounded by the lens 325′, it is represented in a different way inFIG. 4.

The surface mount portions 310 are formed of Au, Ag, Cu, Al or the like.The lens 325′ may be formed of thermosetting resin such as silicon,epoxy, PC and PMMA or thermoplastic resin. Further, as described above,the surface mount portions 310 are formed in a shape of

and ‘⇓’,

or the like.

Further, although the light emitting portion 410 is formed on thesubstrate 400 while being in contact with the substrate 400 in FIG. 4,the light emitting portion 410 may be formed while be spaced from thesubstrate 400. Further, in order to position the light emitting portion410 in the lens 325′ as shown in FIG. 4, a space for the light emittingportion 410 should be formed in the lens 325′. Thus, for the manufactureof the lens, in the lens manufacturing method of the above-describedembodiment, a protruded portion may be formed at a central portion ofthe first mold to form an empty space at the center of the lens.Further, although the lens 325′ is represented in a hemispherical shape,the lens 325′ may be formed in a spherical or non-spherical shape, or ina shape having sectional curvature or bisectional curvature, preferably,having at least one curvature. The lens 325′ should be fixed on thesubstrate 400 through the surface mount portions 310. Further, althoughtwo surface mount portions 310 are shown in FIG. 4, at least one surfacemount portions may be disposed as described above. Further, the lightemitting portion 410 should be a device capable of emitting light, forexample, a light emitting diode (LED).

The light emitting device package according to the embodiment of thepresent invention has the following effects.

Since the lens is fixed on the substrate through the surface mountportions in the above embodiments, the lens can be fixed without usingan adhesive differently from a conventional case. Thus, the lens isaccurately and firmly fixed at a specified position on the substrate torefract light emitted from the light emitting portion, thereby emittinglight at a designed angle.

According to the lens, the manufacturing method thereof and the lightemitting device package of the present invention, the light emittingdevice and lens can be arranged accurately on the substrate. Also, thelight emitting device and lens can be easily and inexpensively arrangedon the substrate.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the inventions. Thus, itis intended that the present invention covers the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

1. A light emitting device package comprising: a substrate; a lightemitting portion disposed on the substrate; a lens covering over thelight emitting portion so as to refract a direction of light emittedfrom the light emitting portion.
 2. The light emitting device packageaccording to claim 1, wherein an upper surface of the light emittingportion is substantially planar.
 3. The light emitting device packageaccording to claim 1, wherein an upper surface of the light emittingportion is contacted with the lens.
 4. The light emitting device packageaccording to claim 1, wherein an entire lateral surface of the lightemitting portion is contacted with the lens.
 5. The light emittingdevice package according to claim 1, wherein the light emitting portionis located at a central portion of the lens.
 6. The light emittingdevice package according to claim 1, wherein the lens has an empty spacewith a prescribed depth at a central portion of a lower surface of thelens.
 7. The light emitting device package according to claim 6, whereinan entire upper surface and a part of a lateral surface of the emittingportion are located in the empty space of the lens.
 8. The lightemitting device package according to claim 1, wherein an entire uppersurface and a part of a lateral surface of the emitting portion aresurrounded by the lens.
 9. The light emitting device package accordingto claim 1, wherein an upper surface of the lens is substantially acurved surface.
 10. The light emitting device package according to claim1, wherein a thickness of the lens is decreased from an inward portioncorresponding to the light emitting portion to an outward portion. 11.The light emitting device package according to claim 1, wherein athickness or a height of the lens is different from that of thesubstrate.
 12. The light emitting device package according to claim 1,wherein an entire thickness or a height of the lens is greater than thatof the substrate.
 13. The light emitting device package according toclaim 1, wherein a thickness of the lens is different from that of thelight emitting portion.
 14. The light emitting device package accordingto claim 1, wherein a thickness of the lens is greater than that of thesubstrate.
 15. A light emitting device package comprising: a substrate;a light emitting portion disposed on the substrate; a lens covering overan upper surface and a part of a lateral surface of the light emittingportion.